Robles struck the decisive goal just before half time at Park Hall last night as Saints made it seven wins from as many league games in the early weeks of the campaign.
Scott Ruscoe’s side – yet to concede a league goal this season – are now two points clear of Nomads, the reigning champions, and also have a game in hand.
Home goalkeeper Paul Harrison had to be alert to make an early double save, before Aeron Edwards, facing his former club, drove a shot over the bar for the visitors from just outside the penalty area.
Sameron Dool was next to go close for Nomads with a low shot into the side netting.
Saints made the breakthrough three minutes before the interval as Robles found the net.
A corner from the right fell to Jon Routledge and his effort was instinctively turned home from close range by Robles, reacting quickest at the far post.
Nomads chased an equaliser in the second half and John Disney went close with a shot on the turn just wide.
But TNS once again defended impressively to secure three more points and they almost added to their lead in the closing stages when Adrian Cieslewicz saw a shot come back off a post.
Saints are quickly back in action when they travel to Aberystwyth Town on Friday night.
TNS: Harrison, Harrington, Hudson, Astles, Marriott, Smith, Routledge, Redmond (Holland), Robles, Ebbe (Draper), Cieslewicz.
Subs not used: Clark, Boateng, Rees, Cornish, Williams.